High-voltage air blast circuit breaker having the blast valve arranged at line potential



Sept. 18, 1951 JANssoN 2,568,008

G. HIGH-VOLTAGE AIR iLAST CIRCUIT BREAKER HAVING THE BLAST VALVEARRANGED AT LINE POTENTIAL Filed lay 22, 1948 4 SheetSfSheet l ATTORNEYSept. 18, 1951 G. E. JANssoN HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKERHAVING THE BLAST VALVE ARRANGED AT LINE POTENTIAL 4 Sheets-SheefI 2Filed llay 22, 1948 u M, 3 0N 6 o m H n .n 3 6 f M H ////v// P. 6 M

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Sept, 18, 1951 G. E. JANssoN HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKERHAVING THE BLAST VALVE ARRANGED AT LINE POTENTIAL Filed lay 22, 1948////////////////////////aan m 6 u a w Sept 18, 1951 G. E. JANssoN2,568,008

HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKER HAVING THE BLAST VALVE ARRANGEDAT LINE POTENTIAL Filed lay 22, 1948 4 Sheets-Sheet 4 Patented Sept. 18,1951 HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKER HAVING THE BLAST VALVEARRANGED AT LINE POTENTIAL Gustav E. Jansson, North Quincy, Mass.,assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., acorporation of Delaware Application May 22, 1948, Serial No. 28,666

19 Claims.

This invention relates in general to circuit breakers, and moreparticularly to the operating means for the circuit breaker contacts andfor a valve controlling the production of a gas blast for extinguishingthe arc.

In circuit breakers of the gas blast type gas under pressure isgenerally stored in a reservoir or tank which is arranged substantiallyat ground potential, and the arc extinguishing blast of gas underpressure is conducted through an insulating blast passage from saidreservoir or tank adjacent to the point of separation of the arcingcontacts. In order to achieve high speed operation and high interruptingcapacity, it is desirable to provide gas blast circuit breakers withmeans which permit minimizing the interval f time required for the arcextinguishing blast passing through the blast valve to reach the arc gapas well as with means which permit minimizing the difference betweenstatic tank pressure and blast pressure. High speed operation calls alsofor timing of the sequence of blast initiation and arc initiation with ahigh degree of accuracy. It is, therefore, one object of the presentinvention to provide a circuit breaker which permits minimizing both theinterval of time required for the arc extinguishing blast to reach thearc gap as well as the difference between static tank pressure and blastpressure and which, in addition thereto, permits timing of the sequenceof blast initiation and arc initiation with a high degree of accuracy.

Another object of the invention is to provide a circuit breaker of thegas blast type having the blast valve arranged at the downstream end ofthe insulating -blast passage and having means for correlating with ahigh degree of accuracy the time of opening of the blast valve and thetime of opening of the contacts.

Y Still another object of the invention is to provide a circuit breakerof the axial gas blast type suitable for outdoor service and having acommon control or operating means for both the movable contact and theblast valve that is simple and rugged and capable to withstand anypunishment resulting from severe atmospheric conditions.

Further objects and advantages will readily become apparent upon readingof the following specification taken in conjunction with the drawings,in which:

Fig. l is a diagrammatic side elevation, partly in cross section, of anair blast circuit breaker of the axial blast type designed for outdoorservice, and of aA pneumatic mechanism for operating that circuitbreaker;

Fig. 2 is a perspective view of a pair of cams and push rods formingpart of the circuit breaker structure shown in Fig. 1;

Fig. 3 shows in side elevation, and partly in cross section. amodiiication of the structure shown in Fig. 1, the arcing contacts beingshown in their closed position;

Fig. 4 is a representation of the same structure as that shown in Fig. 3with the arcing contacts shown in their open rather than their closedposition;

Fig. 5 shows in side elevation, partly in cross section, -anotherembodiment of the present invention;

Fig. 6 is a cross section taken along the line VI--VI of Fig. 5;

Fig. 7 shows partly in side elevation and partly in cross section stillanother modication of the present invention;

Figs. 8 and 9 are horizontal sections taken along lines VIII-VIII andIX-IX, respectively, of Fig. 7, to show more clearly the shape of thecam means forming part of the structure of Fig. '7, said cam means beingshown in Figs. 8 and 9 in contact closed position;

Figs. 10 and 11 are likewise horizontal sections taken along linesVIII-VIII and IX-IX, respectively, of Fig. 7, but showing said cam meansin contact open position;

Fig. 12 is a vertical section along line XII-XII of Fig. 7;

Fig. 13 shows in front elevation and partially in cross section, on alarger scale, a detail of the structure of Fig. 7;

Fig. 14 is a horizontal section taken along line XIV-XIV of Fig. 13;

Fig. l5 is a side elevation, partly in cross section, of an axial typeair blast circuit breaker involving the principles of the presentinvention;

Fig. 16 is a horizontal section along line XVI- XVI of Fig. 15; and

Fig. 17 is a vertical section along line XVII-- XVII of Fig. 15.

Referring now to Figs. 1 and 2 of the drawing, the circuit breakercomprises the circuit breaker AShaft 23 is journaled in been designatedgenand the operating structure which has been designated generally byreference sign 2. Air under pressure stored in tank 3 may be used forproducing an arc extinguishing blast through the gap formed betweenarcing contacts 4 and 5 upon separation thereof as well as for actuatingthe operating structure 2. The passage 6 for supplying the arc gapformed between contacts 4 and 5 with air under pressure is in'partdefined by blast tube 1 and in part dened by a hollow supportinginsulator 8. Insulator 6 supports a casting 9 which defines an extensionof passage 6 and forms the seat I for movable valve element Valveelement |I is adapted to be operated by stem |2 and is, normally biasedto the closed position thereof by helical spring I3. Casting 9accommodates a toggle mechanism which has been indicated generally byreference character I4.

Toggle mechanism I4 is adapted to be operated by push rod I5, and whenthat rod is moved from left to right, as seen in Fig. 1, togglemechanism I4 is caused to collapse and contact 5 is caused to separatefrom contact 4. Helical spring I6 arranged in a cylinder I1 formed by aportion of casting 9 acts through piston I9 upon toggle mechanism I4 andbiases movable contact 5 to closed contact position. Casting 9 supportsan insulator I9 `which, in turn, supports stationary nozzle contact 4.r'I'he top of insulator I9 .is provided with a hood structure '20defining exhaust passage a for the products of arcing.

Stem I2 and push rod I5 are each provided with a roller |2a and i5c,respectively. Roller I2a is adapted to engage a cam 2| and roller |5a isadapted to engage a cam 22. Roller I2a is carried by stem I2 by means ofan intermediate lever 63 pivotally supported by stem I2 by means of pin64. Lever 63 has a nose-shaped abutment 66, and is acted upon by biasingspring 65 tending yto rotate lever 63 about pivot pin 64 so as vto causestem I2 to be engaged by abutment 66. Cams 2| and '22 are supported byshaft 23 which, in turn, is supported by insulator 24. bearings and 26on arms 21 and 28 which form integral parts of casting 9. Insulator 24is supported by a shaft 29 journaled' in bearing 30 and adapted to berotated by a fluid motor which has generally been indicated by referencesign 3 I.

Fluid motor 3| comprises a cylinder 32, a piston 33 movably arranged insaid cylinder, a piston rod 34 attached to said piston, and a slidevalve 35 operatively connected to said piston rod. Motor 3| is adaptedto be supplied with air under pressure from tank 3 through a solenoidtrip valve 36 and pipe 31. The left side of cylinder 32 is adapted to besupplied with air under pressure from tank 3 through closing solenoidvalve 38, pipe 39, a passage defined by a portion of the housing of alockout valve which has been indicated generally at 40, and pipe 4 I.

The straight line motion of piston 33 of fluid motor 3| is convertedinto a rotary motion of shaft 29, insulator 24 and shaft 23 by means ofa crank mechanism 42. Pipes 45 and 46 interconnect cylinder 32 of iluidmotor 3| with the cylinder 43 of a` second fluid motor which has beenindicated generally by reference character 44. Pipes 45 and 46 are bothcontrolled by a common slide element 41 of lockout valve 40. Said slideelement 41 is biased by helical spring 48 to the right position thereofand can be actuated toward the left by -a third uid motor indicatedgenerally at 50 and comprising a cylinder 5| and a piston 52. Cylinder5| of fluid motor 56 can be supplied with air under pressure from tube31 through branch tube 31a.

Piston 53 in cylinder 43 of uid motor 44 actuates a rotatable shaft 54by means of piston rod 55 and crank mechanism 56. Piston rod 55 controlsslide valve 51 for venting cylinder 43. Shaft 54 operates 'a rotatableinsulator 58 which actuates bevel gear 59 for operating movable contact60 of a disconnect switch indicated generally at 6|. Movable contact 60of disconnect switch 6| is adapted to cooperate with stationary contact62 for closing the circuit,

Fluid motor 2| is provided with a pair of ad- .justable needle valves 69permitting to bleed fluid under pressure from cylinder 32. In a similarway and for the same purpose, cylinder 43 of fluid motor 44 is providedwith a. pair of needle valves 10.

The operation of the arrangement shown in Figs. 1 and 2 is as follows:Upon energizing of solenoid valve 36, air under pressure rushing throughpipe 31 moves piston 33 from the right to the left. This causes shaft 23to be rotated through crank mechanism 42, shaft 29 and insulator 24.Rotation of shaft 23 effects sequential opening of blast valve IIJ, andseparation of contacts 4, 5 by means of cam 2| and stem I2 and cam 22and push rod I5. This sequence of operation is positively predeterminedby the shape of cams 2| and 22. Since blast valve I0, il is situated atthe downstream end of blast passage 6 immediately adjacent to contacts4, 5, the time required for the blast to reach 'the gap formed betweenthe separated contacts 4, 5 is minimized or, in other words, the speedof operation of the breaker is increased.

The ilow of air under pressure through pipe 31 and branch pipe 31acauses piston 52 of motor 50 to move from right to left, and this causesslide valve element 41 to block tube 46 and to open tube 45. Upon apredetermined travel of piston 33 of iiuid motor 3| to the left, airunder pressure is allowed to flow from cylinder 32 of uid motor 3|through pipe 45 to cylinder 43 of fluid motor 44. This causes movementof piston 53 of iiuid motor 44 from left to rightre sulting in clockwiseactuation of contact 60 of disconnect switch 6| through piston rod 55,crank mechanism 56, shaft 54, insulator 56 and bevel gear 59.-Sequential opening of arcing contacts 4, 5 and disconnect contacts 60,62, is effected by reason of the fact that admission of iluid underpressure to fluid motor 44 for operating the latter is controlled by theuid motor 3| for operating the former.

Slide valves 35 and 51 permit venting of cylinders 32 and 43 of fluidmotors 3| and ,44, respectively, prior to the end of the respectiveopening strokes of said iluld motors. As pistons 33 and 53 of fluidmotors 3| and 44 approach their respective open contact positions, slidevalves 35 and 51 close the ports at the far ends thereof. Consequently,air cushions are formed on one side of pistons 33 and 153 whichdecelerate the moving elements that are associated with said pistons andoperate as shock absorbers. These air cushions are controlled byadjustable needle valves 69 and 10, respectively, which per- 'mitcomplete bleeding oi of 'the cushion air upon completion of the openingstrokes of fluid motors 3| and 44, respectively. When the disconnectcontacts 60, 62 have parted a safe distance, precluding any restrikingacross thev air gap formed therebetween, blast valve element II is resetby the action of biasing spring I3 as a result of the particular shapeof cam 2|. Cam 22, however, compels contacts 4, 5 to remain in the openposition thereof until closing solenoid valve 38 is energized.

To close the circuit breaker, closing solenoid valve 38 is energized.This permits air under pressure to flow through pipe 39 to the left endof lockout valve 40, resulting in a movement of valve element 41 fromleft to right. Air under pressure flowing through pipes 39 and 4I thencauses piston 33 of fluid motor 3| to move from left to right.Consequently, piston rod 34, crank mechanism 42, shaft 29, insulatingcolumn 24, shaft 23, cam 22, roller |5a, push rod I5 and togglemechanism I4 move contact 5 into engagement with contact 4. Blast valveI0, II

is not opened during the closing stroke of fluid motor 3| on account ofthe resilient pivotal connection between valve stem I2 and rollercarrying lever 63.

By reason of the movement of the valve element 41 from left to right,pipe 45 is blocked and pipe 46 is opened. Upon a predetermined travel ofpiston 33 of fluid motor 3|, air under 4pressure flowing through pipes39 and 4I and cylinder 32 is admitted through pipe 46 to cylinder 43 offluid motor 44. This particular feature causes, during the circuitclosing process, a sequential operation of fluid motors 3| and 44. Themovement of piston 53 of uid motor 44 from right to left causes pistonrod 55, crank mechanism 56, shaft 54, insulator 58 and bevel gear 59 tomove the movable contact 60 of disconnect switch 6I to the closedposition thereof, thus completing the circuit closing operation.

During the initial stage of the circuit closing operation, slide valves35 and 51 permit effective venting of the sides of cylinders 32 and 43toward which pistons 33 and 53 are being moved. Said slide valves,however, close the ports at the nearends thereof during the final stageof the circuit closing operation, thus causing formation ofdecelerating, shock absorbing air cushions at the sides of cylinders 32and 43 toward which pistons 33 and 53 travel. These air cushions aregradually bled off through needle valves 69, 1li. Upon closing ofcontacts 4 and 5 the required contact pressure is maintained by springI6 in housing I1.

It is necessary that an opening operation should always take precedenceover, or predominate over, a closing operation. In other words, openingshould always be effected in response to a tripping impulse,irrespective of whether or not the closing solenoid valve is energizedat the time. Assuming a closing impulse is given while a fault prevails,the opening 'impulse resulting from the fault condition shouldpredominate over the closing impulse, even though the closing impulse ismaintained continually.

Lockout valve 40 serves this particular purpose. When tripping solenoidvalve 36 is energized, piston 52 moves slide element 41 from right toleft, thus preventing fluid motors 3| and u from being supplied withclosing air. If solenoid valves 36 and 38 are energized simultaneously,opening takes precedence because the effective fluid pressure reactivearea of piston 52 is considerably larger than the effective fluidpressure reactive area of the left end of slide element 41. In otherwords, in the event of conflicting operating or control impulses the 6opening impulse will always predominate, a larger effective fluidpressure reactive area being associated with said impulse.

The same reference characters having been applied to like parts in allthe figures, no detailed description of the arrangement of Figs. 3 and 4is required inasmuch as it is in substance the same as that shown. inFigs. 1 and 2. As shown in Figs. 3 and 4, rod I5'is hingedly supportedby links 1I and 12 which are pivoted at 13 and 14, respectively. Shaft14 is adapted to operate a toggle I4 which, in turn, is adapted tooperate contact 5. Piston I8 which is acted upon by helical spring I6arranged within cylinder I 1 is provided with a piston rod |8a connectedto rod |5 by means of link 15. Rod I5 is adapted to be operated by cam22 engaging roller I5a on rod I5. When cam 22 is rotated by shaft 23,rod I5 changes slightly its level since both its points of support movealong circular paths, but cam 22 is so designed that a point of itssurface is always in engagement with roller I5a.

Rotation of insulating column 24 in one direction causes sequentialopening of blast valve I0, II, separation of contacts 4y 5, andreclosing of blast valve IIJ, II. Rotation of insulating column 24 inthe opposite direction 'causes reengagement of contacts 4, 5 without,however, affecting blast valve I0, II. When column 24 is rotated incontact closing direction, rbller carrying arm 63 pivots about pin 64,thus; precluding opening of blast valve I0, I I.

The structure shown in Figs. 3 and 4 is supposed to be associated withan operating mechanism and a disconnect switch capable of performingsubstantially the same functions as the operating mechanism and thedisconnect switch shown in Fig. l. The operating mechanism anddisconnect switch have been omitted in Figs. 3 and 4 for simplifyingthese figures.

Referring now to Figs. 5 and 6, tubular insulator 8 4defines blastpassage 6 and supports casting 9 forming a housing for a blast valvewhich has been generally indicated by reference character.16. Blastvalve 16 comprises movable valve element II which is acted upon byhelical biasing spring I3 tending to press valve element II againstvalve seat I0. Normally, air under pressure acts upon both the right andleft end surfaces of valve element II. The effective area. of the rightfluid pressure reactive surface of valve element I I is smaller than theeffective area of the left pressure reactive surface thereof. However,the air pressure tending to move valve element II from its normalposition shown in Fig. 5 to the right is much less than the sum of theair pressure and the pressure of spring I3 both tending to press valveelement I I to the left against valve seat I0.

The space situated at the right side of valve element II is adapted tobe vented by means of pipe 11, auxiliary valve chamber 18 and an orice|35 controlled by valve element 19.` Valve element 19 is adapted to beoperated by means of stem resting in slide bearings 8|. Stem 80, inturn, is adapted to be operated by a crank mechanism which has generallybeen indicated at 82. Crank mechanism 82 is associated with an operatingshaft 23 adapted to be operated by insulating column 24. The right endof stem 8l is surrounded by a helical biasing spring I|3 of which oneend rests on a collar 80a on stem 88, while the opposite end restsagainst valve housing 18.

Upon rotation of shaft 23 in clockwise direction (as seen in Fig. 9)stem 80 moves to the right against the action of biasing spring l|3 andmoves valve element 19 from the left valve seat I8 to the right valveseat 84 of valve housing 18. Consequently, pipe 85 interconnecting blastpassage 8 with valve housing 18 is blocked and valve housing 18 ventedto atmosphere. This causes the pressure on valve element directed fromleft to right to exceed that directed from right to left, resulting inrapid opening of blast valve 18. The blast of air under pressure whichis admitted from blast passage 6 to the gap formed between separatedcontacts 4, 5 tends to extinguish the arc which is initiated uponparting of movable contact 5 from stationary'contact 4.

Separation oi contacts 4 and 5 is effected by an arm 86 of crankmechanism 82. Arm 98extends into a U-shaped abutment member 81 formingan integral part of rod I5 for actuating a contact operating togglemechanism which has generally been indicated at |4. That togglemechanism comprises link 89 adapted to operate links 89 and 90, of whichthe former is adapted to operate two links 9| and 92. Links 89 and 90are joined together at 93 and link 90 is fulcrumed at 94, in casting 9.Links 89 Aand 9| are joined together at 95, and link 9| is fulcrurned at98, in casting 9. Links 9| and 92 are joined together at 91, and link 92is pivotally connected at 99 to movable contact 5. Arm 86 and U-shapedabutment member 91 form a lost motion connection between shaft 23 andlink 98 which is responsible for a small time delay between opening ofblast valve 16 and separation of contacts 4 and 5.

When crank mechanism 82 is rotated in clockwise direction (as seen inFig. 6), arm 86 moves a predetermined distance before acting upon rodi5; then it engages the left abutment surface of member 81 moving rod |5from right to left. Rod |5 acts upon piston i9 which, in turn, acts uponspring I8 in spring housing |1.A Spring I9 provides the necessarycontact pressure in the closed position of the breaker and is compressedby the action of arm 96 during the circuit interrupting operation. Whenlink 88 is actuated by rod |5 to the left, toggle 89, 90 collapses. Thiscauses rotation of link 9|- about pivot 90 in a clockwise direction (asseen in Fig. 5), resulting in downward pulling of the movable contactwhich has been generally indicated at 5.

Movable contact 5 comprises a radially inner portion 99 and a radiallyouter portion |00. The radially outer portion is telescopically arrangedin a cylindrical guiding member l0 i. The radially inner portion 99 is,in turn, telescopically arranged in the radially outer portion |00.Spring |02 which is arranged between portions 99 and |00 biases theformer in upward direction. As clearly shown in Fig. 5, there is acertain axial play or lost motion between portions 99 and |00 and thesetwo portions are provided with cooperating abutments 99a and |00a,respectively, which limit relative movement of portions 99 and |00 whenthe latter is disengaged from tubular stationary contact 4. i

Guiding member |0| is providedwith spring biased contact segments |02for reducing the contact resistance between that member and radiallyouter portion |00. In a similar way, radially outer portion '|00 isprovided with contact segments |03 for reducing the contact resistancebetween that portion and the radially inner portion 99. The radiallyinner portion 99 serves as arcing contact while the radially outerportion III serves as current carrying contact. When the radially outerportion is actuated in a downward direction by toggle mechanism |4, theradially outer portion |00 separates first from stationary nozzlecontact 4. Upon a predetermined downward travel of portion |00 abutment|00a thereof engages the fianges or abutment 99a of portion 99, thuscompelling the latter to separate from nozzle contact 4.

In order to causeireclosing of the blast valve 18 at thel end of thecircuit interrupting operation, an intermediate link l |0 isarrangedbetween arms 96 and 86a of crank mechanism 82, and arm 86a isprovided with an abutment member adapted to be engaged by a stationaryabutment |2, Abutments and ||2 cause buckling of the toggle formed bymembers 89a, ||0 at the end of the circuit opening operation. This, inturn, permits spring ||3 to move stem 80 to the left, thus moving valveelement 19 from right valve seat 84 to left valve seat 93. Consequently.compressed air is being admitted to blast valve 16 through passagesI 85and 11, resulting in closing of blast valve 16, thus precludingcontinued consumption of compressed air upon interruption of the circuitand interposition of a suflicient amount of circuit insulation.

The structure shown in Figs. 5 and 6 is supposed to be associated withan operating mechanism and a disconnect switch capable of performingsubstantially the same functions as the operating mechanism anddisconnect switch shown in Fig. l. Upon rotation of insulating co1- umn24 in a clockwise direction (as seen in Fig. 6) crank mechanism 82 movesstem 90 from left to right, thus causing closing of pipe 85 by valveelement 19 and venting of valve housing 18. Consequently, blast valveelement moves from left to right, thus admitting a blast of air underpressure adjacent the contacts 4, 99 of the circuit breaker. lContactseparation is effected shortly upon blast initiation by arm 86 engagingabutment member 81 and moving the same from right to left. When abutmentmember hits upon abutment member |2 and toggle 96a, I0 buckles, spring||3 is free to move valve element 19 from right to left. This stopscontinued venting of blast valve 16 and reclosing thereof on account ofthe admission to it of air under pressure through pipes 95 and 11, asstated above. Reclosing of the contacts is effected by causing rotationof insulating column 24 in a counterclocli'.-n wise direction (as seenin Fig. 6)

Referring now to Figs. 7 to 14, a blast valve generally designated byreference 16 and comprising housing 9 and movable valve element isarranged coaxially with respect to hollow insulator 8 defining blastpassage 6. Such a coaxial arrangement of a blast valve and a blastpassage makes it possible to obtain an almost straight blast path fromthe tank (not shown) for storing air under pressure to the gap formedbetween the separated contacts Where arc extinction is to take place. Inthe structure shown in Fig. '7 the blast valve, the contact operatingtoggle mechanism and the contact arrangement itself are of the samegeneral type as in the structure shown in Fig. 5 and the same referencecharacters are applied to designate like parts. In view thereof there isno need for a detailed description of the blast valve, the contactoperating toggle mechanism and the contact arrangement shown in Fig. 7.Casting 9 forms also a housing 19 for an auxiliary valve includingmovable valve element 19. That auxiliary valve comprises a 75 valve seat83 on its left side and a valve seat 84 on its right side. 'Valveelement 19 is carried by stem 80 and restsenormally against left valveseat 03. In that position of valve element 19, blast passage 6communicates with the spaces on both the axially upper and lower sidesof valve element Air under pressure from the tank (not shown) passesthrough blast passage 6, a passage |90, about valve element Il, a valveseat 84, and a passage |94 to the lower side of valve element The fluidpressure exerted on the lower iiuid pressure reactive surface of valveelement plus the force of helical spring i3 acting in the same directionexceeds by far the fluid pressure exerted on the upper fluid pressurereactive surface of valve element tending to move the same in a downwarddirection against the action of spring I3. Moving of valve element 19from left to right results in venting to atmosphere of the spaceadjacent the lower uid pressure reactive surface of valve element I I.Now the pressure upon the upper fluid pressure reactive surface of valveelement II exceeds by far the force of spring I3. The latter, therefore,is compressed and an arc extinguishing blast is allowed to fiow throughblast valve 16 straight toward the arcing zone which is situated aboveit.

The mechanism for causing sequential opening of the blast valve and ofthe contacts and thereafter reclosing of the blast valve is operated bythe rotatable insulating column 24 adapted to rotate control shaft H6.Control shaft ||6 is passed at right angles through cutout portions ofmembers I|9 and |29, which portions are bounded laterally by curvedsurfaces I I1 and IIB in the nature of cam surfaces. Members I I9 and|29 are each arranged in one of a pair of tubular extensions |2| and|22, of casting 9. Control shaft I'I6 is adapted to operate members I I9and |29 by means of arms |23 and |24, respectively. Arm |23 is adaptedto engage cam surface ||1 of cam members |I9 and arm |24 is adapted toengage cam surface ||8 of cam member |29. To this end and in order tominimize friction between relatively movable cooperating parts, arms |23and |24 are provided, at the radially outer ends thereof, each with aroller |25 and |26, respectively. Arm |23 is keyed to control shaft I|6and arm |24 is loosely mounted upon said shaft and adapted to be rotatedby said shaft through the intermediary of a ratchet mechanism. rIhatmechanism has been generally designated in Fig. '1 by reference sign |21and has been shown on an enlarged scale in Figs. 13 and 14.

Rotation of control shaft |6 in a clockwise direction (as viewed inFigs. 8 to 11) causes movement of cam member I|9 from its right positionshown in Fig. 8 to its left position shown in Fig. l0. Cam member |'I9is moved against the action of biasing spring |28 and actuates thetoggle mechanism controlling rod |29 from right to left. Tubularextension |2| is provided with two guide members |39 forming a groove|3I therebetween adapted to receive cam member |I9 and to guide it alonga straight path.

In a similar way, tubular extension |22 is provided with two guidemembers |32 forming a groove |33 therebetween adapted to receive cammember and vto guide it along a straight path. Cam member |29 carries abracket |34 having a central bore for receiving the stem 89 of valveelement 19 and forming abutments for one end of each of two springs |36and |31. Spring |36 rests with its opposite end against a collar |38 ofstem 89. In a similar way, one end 'of spring |31 rests against a collar|39 on stem 80. If

bracket |34 is in its left position shown in Fig. 9, spring |36 isslightly compressed, and valve body is being pressed against left valveseat 83 by the pressure that prevails in housing 18. If arm |24 androller |26 are rotated in a clockwise direction (as viewed in Figs. 9and ll), spring |31 is slightly compressed and4 valve body' 19 heldagainst right valve seat 84.

As shown in Figs. 9 and l1, a portion of the cam surface ||8 of cammember |20 forms an abutment I I8a. adapted to engage roller |26 whenspring |59 interconnecting arm |24 and cam member |29 is in itscontracted position.

Referring now more particularly to Figs. 13 and 14, the lower surface ofroller carrying arm |24 is provided with a depending projection |40adapted to be engaged by ratchet pawl |'4|. Ratchet pawl |4| ispivotally mounted at |69 on a bracket I6| on a collar |62 pinned at |63to the control shaft ||6. Thus control shaft ||6 and arm |24 are coupledwhen projection |40 is engaged by pawl |4I` and the latter is rotated bycontrol shaft ||6 in a clockwise direction, as viewed in Fig. 14. Spring|64 tends to keep ratchet pawl |4| in engagement with projection |49.Ratchet pawl |4| is provided at the lower end thereof with an abutment|65 adapted to engage stationary abutment |66. Upon rotation of controlshaft ||6 in a clockwise direction, as viewed in Fig. 14, abutment |65engages abutment |66, resulting in disengagement of pawl |4I fromprojection |49.

The operation of the arrangement illustrated in Figs. '7 to 14 is asfollows: Upon rotation of insulating column 24 in a direction from theclosed to the open position thereof, the blast valve control means aremoved from their position shown in Fig. 9 to their position shown inFig. 11. This results in opening of blast valve 16. thus establishing anarc extinguishing air blast. Rotation of insulating column 24 from theclosed to the open position thereof results also in moving the contactoperating means from their position shown in Fig. 8 to their positionshown in Fig. 10. Complete separation of contacts 4, and 99 and |00,respectively, is achieved at a time when arm |23 has rotated about apredetermined angle. While insulating column 24 and control shaft I6 arestill being rotated in a contact separating direction, abutment |65engages abutment |66, resulting in disengagement of pawl |4| fromprojection |49. Hence arm |24 and cam member |20 are free to returnunder the action of springs |59 and |39 to their initial position shownin Fig. 9. This causes valve element 19 to be moved to the leftandpressure to be built up on the axially lower surface of valve elementand, after a given time delay, sufcient to effect circuit interruptionand to interpose circuit insulation by means of a disconnect switch orotherwise, blast valve 16 recloses and stops further escape of air underpressure out of blast passage 6.

Since the space within casting 9 situated between blast valve 16 and thegap formed between separated contacts 4 and 99 can be kept withinrelatively narrow limits, there is but little pre-expansion ofcompressed air during its flow from blast valve 16 to the arcing zone.This tends to minimize the drop in pressure between these two points or,in other words, to increase the interrupting efficiency.

Referring now to Figs. 15, 16 and 17, reference character 4 indicates astationary tubular contact and reference character 5 indicates acooperating movable contact. Movable contact 0 is supported by adiilerential type piston |10 which is biased in an upward direction byspring I1 I. Piston |10 is movably arranged in a cylinder |12 havinglateral holes |13. Movable contact 5 is tubular and surrounded by twogarter springs |14 which are acted upon by spring means |10 tending toseparate garter springs |14 in a direction longitudinally of contact 5.Garter springs |14 are current carrying elements for conductivelyconnecting movable contact and cylinder |12. Spring means |15 pressgarter springs |14 against inclined surface elements on cylinder |12,thus transmitting a force component on garter springs |14 in a directionradially of contact 8. Spring means |15, therefore, have the tendency topress garter springs |14 against cylinder |12 as well as against contact5, which minimizes the resistance to current flow between these twoparts. Cylinder |12 is enclosed in a tubular insulator I9, leaving anannular space |18 between the radially outer surface of cylinder |12 andthe radially inner surface of insulator I '9.

A hood 20 dening passages 20a enclosing cooling plates |11 for theproducts of arcing is arranged above stationary contact 4 and insulatorI9. The upper portion of movable contact 5 is surrounded by an annularinsulating throat |18 which helps to deionize the arc gap formed betweencontacts 4 and 5 upon separation thereof. Insulator I9 is held in properposition by clamping means |19. A casting |80 arranged-below cylinder|12 defines two ducts or passages I8| which permit a flow of compressedair from a source of compressed air (not shown) to the gap formedbetween contacts 4 and 5 upon separation thereof. Passages |8| are incommunication with annular space |16 between insulator I9 and cylinder|12, which space forms an immediate coaxial 'extension of passages I8I.Compressed air in space |16 will be admitted through the orices |13 tothe top surface of piston |10. Casting |80 further defines a housing |95for a slide valve element |82 which is adapted to be operated by rotaryinsulating column 24 and crank mechanism |83.

Rotary column 24 shown in Fig. 15 is supposed to be operated in the sameway and by substantially the same means as rotary column 24 of Fig. l.Housing |95 is provided with a port |84 which directly connects passages|8| to housing |95. A port |98 permits compressed air from passages |8|to pass through housing |95 into a lower` end of cylinder |12 when valveelement |82 is in the left hand position as shown in Figs. 15 and 16.Passage |85 permits venting to atmosphere oi' compressed air from theside of cylinder |12 situated below piston in case that valve element 82is moved from its left position'shown in Fig. to the right. If so moved,passage |80 will be uncovered and simultaneously passages |84 will becovered.

It is possible to superimpose a plurality of elements of the kind shownin Figs. 15 and 17, thus forming a circuit breaker column comprising aplurality oi' pairs of cooperating contacts which are connected inseries and form series breaks upon contact separation. Fig. 15 indicatesthe hood and the cooling plates l|11 associated with a pair ofcooperating contacts which may be arranged on a lower level in exactlythe same way as contacts 4 and 5 shown in Fig. 15. 'I'he lower hood 20is formed by the same casting |80 which defines supply passages I8I.Assuming only two circuit breaker elements to be superposed, passages|8| of casting |80 connect the annular space |18 of the lower circuitbreaker element to the annular space |18 of the upper circuit breakerelement illustrated in Figs. l5, 16 and 17, by'bypassing venting hood20. Gas under pressurentering the lower circuit breaker element andparticularly annular space |10 thereof may, in part, escape through thegap formed between the lower contacts 4,` 8 upon separation thereof, andin part rush through passages |8| in the casting |80 to the annularspace |18 of the circuit breaker element mounted immediately above andillustrated in Figs. 15, 16 and 17. The venting structure 20a on the topof the circuit breaker column permits escape to Yatmosphere of the airunder pressure which reaches the top oi the column only through the gapbetween the arcing contacts, i. e., it has no bypass means such aspassages |8| of casting |80. A circuit breaker column of the generaltype here referred to is shown in my U. S. Patent 2,558,757, issued July3, 1951. for Multibreak Gas Blast Circuit Breaker With GroundedOperating Motor. The above mentioned 'patent also shows theconfiguration of casting |80 and of the ducts or passages 8| and of the`passages formed by the lower exhaust hood 20.

The contact arrangement shown in Figs. 15,

16 and 17 and the contact operating and control means shown in thesegures are combined with blast valve and blast valve operating andcontrol means of the kind shown either in Figs. 1,

and 4. In other words, in Figs. 1, 3 and 4, the contact arrangement andthe contact operating andl control means may be substituted by thecontact arrangementand the contact operating and control means shown inFigs. 15, 16 and 17.

The operation of the structure shown in Figs. l5, 16 and 17 to separatethe arcing contacts 4 and 5 is as follows: Rotation of insulating column24 causes blast valve |0 to open by the means fully described inconnection with Figs.l, 2, 3 and 4. Opening of valve I0 results inadmission of air under pressure to passages |8|. Air under pressureentering passages I8I in part rushes through the annular space |16 tothe space immediately surrounding the arcing contacts, and, in part,through the port |13 of cylinder |12 to the space above piston |10. Partof the air under pressure in passage |8| also rushes through port |84,valve housing |95, port |98, and into the lower end of cylinder |12.Thus, air under pressure in passages |8I is admitted to the top as wellas to the bottom of diierential piston |10. Since air pressure isapplied simultaneously to both sides of piston |18 and the pressurereactive areas on both sides of piston I 10 are about the same, contacts4 and 5 will remain engaged for the time being under the action ofbiasing spring |1|. Continued rotation of column 24 causes valve element|82 to be moved to the right from its lett position shown in Figs. 15and 16. This causes blocking of passages |84 and dumping of air from theportion of cylinder |12 situated below difierential piston |10 throughpassage |85 which is Hence differential piston |10 will aseaoos aplurality of superimposed interrupting units,

insulating column 24 will be provided with atacts that it may involveconsists in prevalence of substantially equal pressure conditionsthroughout the entire lengths or height of the circuit breaker column.This can be achieved by permitting a sufficient time delay betweenopening of the blast valve and separation of the arcing contacts.Dumping of compressed air from the spaces |16 inside insulators I9through openings |85 involves evidently a certain time element conduciveto equalization of pressure conditions throughout the length of amultibreak air blast circuit breaker column.

It will be apparent to those skilled in the art that my invention. isnot limited to the particular conditions shown but that changes andmodifications may be made without departing from the spirit and scope ofmy invention, and I aim the appended claims to cover all such changesand modifications.

It is claimed and desired to secure by Letters Patent:

l. In a circuit breaker in combination, a reservoir for gas underpressure, means deflning an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, a pair of cooperatingrelatively movable contacts arranged in the zone of said blast, a motormeans arranged substantially at ground potential, and an insulatingelement adapted adjacent one end thereof to control the operation ofsaid pair of contacts as Well as to control the operation of said valvemeans, and adapted adjacent the opposite end thereof to be operated bysaid motor means.

2. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, a pair of cooperatingrelatively movable contacts arranged in the zone of said blast, a motormeans arranged substantially at ground potential, and an insulatingelement adapted adjacent one end thereof to operate one of said pair ofcontacts and to initiate the operation of said valve means, and adaptedadjacent the opposite end thereof to be operated by said motor means. a

3. In a circuit breaker in combination, a reservoir for gas underpressure,` means dening an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, a pair of cooperatingrelatively movable contacts arranged in the zone of said blast, a motormeans arranged substantially at ground potential, and a rotatableinsulating column arranged generally parallel to said blast passagedefining means, said column being adapted adjacent one end thereof tocontrol the operation of one of said pair of contacts as well as tocontrol the operation of said valve means, and adapted adjacent theopposite end thereof to be rotated by said motor means.

4. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, a pair of cooperatingrelatively movable contacts arranged in the zone of said blast, a motormeans arranged substantially at ground potential, and a rotatableinsulating column arranged parallel to said blast passage definingmeans, said column being adapted adjacent one end thereof to operate oneof said pair of contacts and to initiate the operation of said valvemeans, and adapted adjacent the opposite end thereof to be rotated bysaid motor means.

5. In a circuit breaker in combination, a reservoir for gas underpressure, a hollow insulator in permanent communication at one endthereof with said reservoir, a metal housing arranged at the oppositeend of said insulator, a main valve means enclosed within said housingfor controlling a blast of gas through said insulator and housing, iiuidmotor means for operating said main valve means and forming an integralpart of said housing, an auxiliary valve for initiating the operation ofsaid iiuid motor means, a pair of cooperating relatively movablecontacts arranged in the zone of said blast, a common motor meansarranged substantially at ground potential, and an insulating elementadapted adjacent one end thereof to operate one of said pair of contactsand said auxiliary valve, and adapted adjacent the opposite end thereofto be operated by said common motor means.

6. In a circuit breaker in combination, a reservoir for gas underpressure, a hollow insulator in permanent communication at one endthereof with said reservoir, a metal housing arranged at the oppositeend of said insulator, a main valve means enclosed within said housingfor controlling a blast of gas through said insulator and housing, fluidmotor means for operating said main valve means and forming an integralpart of said housing, an auxiliary valve for initiating the operation ofsaid fluid motor means, a pair of cooperating contacts arranged in thezone of said blast, a common motor means arranged substantially atground potential, and a rotatable insulating column arrangedsubstantially parallel to said hollow insulator, said column beingadapted adjacent one end thereof to operate one of said pair of contactsand said auxiliary valve, and adapted adjacent the opposite end thereofto be rotated by said common motor means.

'7. In a gas blast circuit breaker, a tubular insulating supportingmember, a pair of cooperating relatively movable contacts supported bysaid member, a reservoir for gas under pressure in permanentcommunication with said member, valve means arranged adjacent thedownstream end of said member for controlling an arc extinguishing blastadjacent said pair of contacts, said valve means being at substantiallythe same potential as at least one of said pair of contacts, a motormeans arranged substantially at ground a reservoir for gas underpressure -substantially at ground potential and in permanentcommunication with one end of said insulating,r member, a main valve forcontrolling an arc extinguishing blast of gas from said insulatingrmember into said chamber dening means and adjacent said pair ofcontacts, said main valve being arrangedadjacent the end of saidinsulating member remote from said reservoir, fluid motor means for'operating/i said main valve arranged adjacent thereto and atsubstantially the same potential as said main valve, an auxiliary valvefor controlling the operation of said fluid motor means, a motor meansarranged substantially at ground potential, and a vertical rotatableinsulating column, one end of said column being adapted to control theoperation of one of said pair of contacts and actuate said auxiliaryvalve, and the other end of said column being adapted to be rotated bysaid motor means.

9. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, a pair of cooperatingrelatively movable contacts arranged in the zone of said blast, a motormeans arranged substantially at ground potential, a rotatable insulatingcolumn arranged parallel to said blast passage defining means, one endof said column being adapted to be rotated by said motor means, a pairof cam means associated with the opposite end of said column, one ofsaid pair of cam means being adapted to control the operation of one ofsaid pair of contacts, and the other of said pair of cam means beingadapted to control the operation of said valve means.

10. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, valve meansarranged adjacent the opposite end of said passage for controlling ablast of gas under pressure issuing therefrom, means defining anextension of said passage substantially parallel thereto and adapted toreceive the blast issuing therefrom, a nozzle contact and a cooperatingplug contact arranged within said extension defining means and closelyadjacent said valve means, operating means for effecting relativemovement between said nozzle contact and said plug contact in adirection longitudinal of said extension, a fluid motor arrangedsubstantially at vground potential, and an insulating co1- umn adaptedto be rotated about the longitudinal axis thereof and arranged generallyparallel to said blast passage and said extension defining means, oneend of said insulating column being adapted to control the operation ofsaid operating means and operation of said valve means, and the oppositeend of said insulating column being adapted to be rotated by said fluidmotor.

11. In a circuit `breaker in combination, a re8 ervoir for gas underpressure, means defining an insulating blast passage communicatingpermanently at one end thereof with said reservoir, a differential valveadjacent the opposite end of said passage for controlling a blast of gasunder pressure issuing therefrom, .an auxiliary' valve adjacent saidopposite end of said passage for venting one side of said differentialvalve, means defining an extension of said passage adapted to receivethe blast issuing therefrom, a nozzle contact and a cooperating plugcontact arranged within said extension defining means and closelyadjacent to said differential valve, operating r means for effectingrelative movement between said nozzle contact and said plug contact in adirection longitudinal of said extension defining means, a fluid motorarranged substantially at ground potential, a transmission adapted to beoperated by said fluid motor, and an insulating column adapted to berotated about the longitudinal 'axis thereof and arranged generallyparallel to said blast passage and extension defining means, one end ofsaid column being adapted to actuate said auxiliary valve and to controlsaid contact operating means, and the opposite end of said insulatingcolumn being adapted to be actuated by said transmission.

12. In a circuit breaker in combination, a reservoir for gas underpressure, a first vertical insulating column defining a blast passagecommunicating permanently at one end thereof with said reservoir, avalve adjacent the opposite end of said passage for controlling a blastof gas under pressure issuing therefrom, said valve including a movablevalve element and guiding means therefor for causing said valve elementto move in a direction longitudinal of said passage, means arrangedcoaxial with respect to to control both said valve and said contactseparating means.

' 13. In a circuit breaker in combination, a reservoir for gas underpressure, blast passage insulating means supported by and in permanentcommunication at one end thereof with said reservoir, a metal housing atthe end of said blast passage means remote from said reservoir, adifferential valve within said housing for controlling a blast of gasunder pressure issuing from said blast passage means, an auxiliary valveadjacent said differential valve for venting one side thereof, a pair ofcooperating contacts arranged to be exposed to said blast of gas,contact separating means arranged within said housing for separatingsaid pair of contacts, a fluid motor adjacent the intake end of saidblast passage means and substantially at ground potential, a

` first rotatable shaft parallel to said blast pasadapted to constitutea common means for actuating said auxiliary valve and for controllingthev lcent said differential valve for venting one side thereof, acontact operating mechanism within said housing, a pair of cooperatingcontacts exposed to said blast of gas and adapted to be separated bysaid contact operating mechanism, a fluid motor adjacent the intake endof said blast passage means and substantially at ground potential, afirst rotatable shaft parallel to said blast passage and adapted to berotated by said fiuid motor, an insulating column supported by andarranged coaxial with respect to said rst shaft, .a second rotatableshaftsupported by said insulating column and arranged coaxial withrespect to said first shaft; means associated with said second shaft forcontrolling both said auxiliary valve and said contact operatingmechanism, said last referred to means including means for causingopening of said differential valve only upon rotation of said secondshaft in one of both directions and means for causing operation of saidcontact operating mechanism upon rotation of said second shaft in eitherof both directions.

15. In a circuit breaker in combination, a reservoir for gas underpressure; means at least in part of insulating material-defining a blastpassage in permanent communication at one end thereof with saidreservoir and adapted to be supplied with gas under pressure from saidreservoir; a blast valve arranged adjacent the opposite end of saidpassage for controlling a blast of gas under pressure through saidpassage; a pair of cooperating contacts arranged in the path of saidblast; a motor operable by gas under pressure comprising a cylinder anda spring biased piston, said motor being arranged immediately adjacentone of said pair of contacts at the potential thereof and adapted toseparate said one of said pair of contacts from the other of said pairof contacts; means for admitting gas under pressure from said blastpassage to said cylinder simultaneously on 'both sides of said piston;means for venting said cylinder on one side of said piston only to causeseparation of said pair of contacts; an insulating column adapted to berotated about the longitudinal axis thereof and arranged generallyparallel to said blast passage, one end of said column being adapted tocontrol said venting means; and motor means substantially at groundpotential operatively related to the other end of said column forrotating said column to cause opening of said venting means to causeseparation of said pair of contacts.

` 16. In a circuit breaker in combination, a reservoir for gas underpressure; means of insulating material defining a blast passage inpermanent communication at one end thereof with said reservoir; valvemeans arranged adjacent the opposite end of said passage for controllinga blast of gas under pressure issuing therefrom; a pair of cooperatingcontacts arranged in the zone of said blast; a motor operable by gasunder pressure and comprising a cylinder and a spring biased piston,said motor being arranged immediately adjacent one of said pair ofcontacts at the potential thereof and adapted to` separate said one ofsaid pair of contacts from the other of said pair of contacts; means foradmitting gas under pressure from said blast passage to said cylindersimultanei isly on both sides of said piston;

lmeans for venting said cylinder on one side of said piston only tocause separation of said pair of contacts; an insiilatingvcolumn adaptedto be rotated about the longitudinal axis thereof and arranged generallyparallel to said blast passage; one end of said column being adapted tocontrol the opera'tion of both said valve means and said venting means,and motor means arranged substantially at ground potential and adjacentthe opposite end of said column for rotating said column to control theoperation of said valve means and of said venting means tocause openingof said valve means and separation of said pair of contacts. f

17. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, a blast valvearranged at the opposite end of said passage for controlling a blast ofgas under pressure issuing therefrom, a pair of cooperating contactsarranged. in the path of said blast, a fluid motor for operating saidblast valve, an auxiliary valve for controlling the operation of saidblast valve'operating fluid motor, a fiuid motor for effecting relativemovement between said contacts, an auxiliary valve for controlling theoperation of said contact operating fiuid motor, a common insulatingelement for actuating both said auxiliary valves, and motor meansarranged substantially at ground potential for operating said commoninsulating element.

18. In a circuit breaker in combination, a reservoir for gas underpressure, means defining an insulating blast passage in permanentcommunication at one end thereof with said reservoir, a blast valvearranged at the opposite end of said passage for controlling a blast ofgas under pressure issuing therefrom, a pair of cooperating contactsarranged in the path of said blast, a fluid motor for operating saidblast valve, said fluid motor including a differential type pistonforming an integral part of said blast valve, an auxiliary valve forcontrolling the operation of said blast valve operating fiuid motor, afluid motor for effecting relative movement between said contacts, saidfluid motor including a differential type piston forming an integralpart of one of said contacts, an auxiliary valve for controlling theoperation of said contact operating fluid.

motor, an insulating column rotatable about the longitudinal axisthereof adapted to actuate both said auxiliary valves, and an auxiliarymotor means arranged substantially at ground potential for rotating saidcolumn.

19. In a circuit breaker in combination, a reservoir for gas underpressure; means at least in part of insulating material defining fablast passage in permanent communication at one end thereof with saidreservoir and adapted to be supplied with gas under pressure from saidreservoir; a blast valve for controlling a blast of gas through saidpassage; a pair of cooperating contacts arranged in the path of saidblast; a first fluid operated motor for operating said blast valve, saidmotor including a differential type piston forming an integral part ofsaid blast valve; an auxiliary valve for controlling the operation ofsaid ilrst motor,l a second iluid oper REFERENCES CITED ated meter foreffecting relative movement be" The following references are of-recordin the tween said pair -of contacts, said second motor me of thispatent:

including a differential type piston forming an integral part of one ofsaid pair of contacts; an 5 UNITED STATES PATENTS auxiliary valve forcontrolling the operation of Number Name Date said second motor; aninsulating column rotat- 2,288,472 MacNeill et al June 30, 1942 ableabout the longitudinal axis thereof adapted 2,419,447 Geyer et al Apr.22, 1947 to actuate both said auxiliary valves; and a motor 2,454,586Amer Nov. 23, 1948 arranged substantially at ground potential for l@2,470,623 Ludwig et al. May 17, 1949 rotating said column.

GUSTAN E. JANSSON.

